7 Causes of Cloudy Pool Water and How to Clear it

A new pool is exciting, but the excitement is dampened by problems that can be easily managed with proper maintenance. Most pool owners learn the hard way that adding chlorine and pool chemicals doesn’t automatically make a pool swim-ready round the clock. And while they can deal with most issues, they find cloudiness to be the most confusing challenge to overcome.

The broad causes of pool cloudiness are microscopic impurities and poor chemical balance. The possible impurities include some that emerge from the pool chemicals. The best way to clear your cloudy pool is to improve its filtration and pH balance. A pool clarifier always helps.

In this article, we will go over the different causes of cloudy pool water alongside the specific signs of each one. Moreover, we will go over the respective ways of fixing each problem, including how to fix cloudiness from:

  • Clogged or damaged water filter 
  • High combined chlorine levels
  • High pool pH
  • Calcium hardness and scaling
  • Presence of dead algae
  • Soap and detergent buildup
  • Poor hygiene of swimmers
  • Dirt and debris

1. Improper Filtration

Most pools that get cloudy have this as their main or secondary reason. If your pool water is dull, unclear, or even powdery, you need to check your pool filter. There are three things that could be wrong with the filtration system:

  • Water circulation is too slow for timely filtering – Your water filter could be perfectly fine, but because of slow filtration might cause water to get dirtier quicker than it gets cleaned. 
  • Your water filter is clogged – Most often, improper filtration happens because the water filter is clogged. In minor cases, simple backwashing can help. In complicated situations, the filter needs to be replaced.
  • The water filter is damaged – The water filter being damaged is not as likely as it being clogged. Still, you cannot rule out the possibility. If you find the water filter in an irreparable condition, you should get it replaced as soon as possible to avoid further damage.

How To Fix This:

Backing washing the filter might help if there is minor clogging. It is the easier step, so it must be tried first. Backwash the filter, remove and clean it if required, and look for improvement in water clarity. If the filter needs replacement, get a new filter. Even if it doesn’t improve the water clarity, it is a necessary step because your water filtration needs to be in shape at all times.

2. Presence of Chloramine (Due to High PH)

When the water pH is imbalanced, the free chlorine in the pool depletes. Once the free chlorine levels are low enough, it forms chloramine after combining with ammonia. Chloramine has a yellowish, cloudy appearance, which can make the water cloudy. This can happen because of too much chlorine or too little free chlorine.

Cloudiness is a symptom more than a problem in this case. If you’re familiar with pool chemicals, you know that chlorine is essential in killing bacteria. When chlorine depletes and chloramine increases, there isn’t enough chlorine to kill microbes. This can make pool water very unhealthy.

How To Fix This:

First, you need to be sure that free chlorine depletion is the problem. Take a chemical reading and verify that the combined chlorine levels are below 0.5 parts per million (ppm). Secondly, you must verify that the pH of the water is no higher than 7.8. At pH over 7.8, the chlorine in your pool is completely ineffective at killing bacteria. 

If none of the readings are off the mark, then chloramine isn’t a contributor to your pool’s cloudiness. If either one is, then you need to fix both. Add chlorine to improve free chlorine levels after adding pool chemicals to lower the pool pH.

3. High Alkalinity and Resultant Scaling

Calcium scaling is another contributor to pool cloudiness that also stems from high alkalinity. When your pool water seems to be cloudy, as if ground chalk is floating in it, you can be sure that high pH scaling is one of the culprits. High pH indicates high alkalinity. And when your pool’s total alkalinity crosses 200 parts per million, calcium scaling becomes evident.

Calcium deposits form in the pool plumbing, which increases the water circulation pressure. As the pipes get narrower, water friction increases in the pool plumbing, and the calcium deposits start to break down and pepper the water flow. Powdery calcium in the water gives it a chalky look commonly cleared by a pool clarifier.

How To Fix This:

First, you should check for scaling in the pool pipes. If there are scales in the pool plumbing, you don’t even need to test the total alkalinity of the pool water. Regardless of how thin or thick the scales are, you should use descaling liquid to clear the deposits. Soon after, you need to balance the pool pH by bringing down the alkalinity. Adding a pool clarifier should be the last step.

4. Dead Algae

This is one of the rarest causes of cloudy pool water but is a cause nonetheless. If your pool gets infested by algae, you end up killing it with an algaecide. But you might not realize that the water is cloudy until the lighting is right. Dead algae turn bluish grey. When enough algae are present in the water, the appearance of the pool is cloudy because of the layer of dead algae.

How To Fix This Problem:

To clear the bluish grey tint of dead algae and make your pool water less cloudy, you should add pool clarifier. If your pool was once covered in algae and you used an algaecide and chlorine shock to get rid of it, then the cloudiness can be because of the dead algae. If algae were never visible at any point, the chances of them being responsible for the cloudiness are low.

5. Soap and Detergents

Soap and body detergents often have a milky appearance. But because the soap-to-water ratio is so steep, it rarely affects the water clarity. The same soap can make a tub cloudy in a few minutes. 

When soap and detergents build up in a pool’s plumbing system, the cloudiness compounds until it becomes visible. The cloudiness created by soap and detergents is quite different from the chalky calcium cloudiness. The water is more translucent when it is milky due to detergents.

How To Fix This:

To fix the cloudiness caused by soap and detergent, you need to get rid of the soap, add pool clarifier, circulate the water more, and add more fresh water to the pool. Balancing pool chemicals after the soap is removed will bring clarity to the water.

You should remove soap from the water with the following steps:

  • Get solid soap out with a skimmer or brush 
  • Add equal parts white vinegar and water to a spray bottle
  • Spray any visibly soapy area
  • Dump the diluted vinegar in the pool and let the water circulate for 24 hours
  • Add pool clarifier
  • Add and balance pool chemicals

6. Impurities From Swimmers

Sometimes, the cloudiness is simply an aggregate of impurities from the swimmers. Think about pool clarity as the lack of visible particles or impurities. If a chunk of dirt falls into the water, it is big enough to be identified as a solid impurity. But if the same impurity is small enough to be seen as an individual unit, it becomes invisible. 

Hundreds of thousands of such impurities collectively produce the illusion of cloudiness. Think of baby powder in a glass of water. Even though the powder doesn’t dissolve in water, it can be dispersed to the point where it interferes with water’s clarity.

Impurities from swimmers can have the same effect. Often, we don’t carry visible dirt on our bodies, especially when we jump into a pool. But there are microscopic particles on our bodies. Usually, the pool filter catches them. But if, for whatever reason, the filtration system doesn’t handle the impurities well, the pool water becomes cloudy.

How To Fix This:

You must fix the water filter or upgrade it to match the pool usage. Aside from that, you can add a pool clarifier as a quick fix. In the long run, you need to maintain better pool hygiene to avoid cloudiness. Very rarely do pool owners need to drain their pools due to swimmer hygiene and impurities.

7. Dirt, Debris, and Active Impurities

As you know by now, swimmer hygiene and impurities can affect pool clarity. The same principle is valid in the absence of swimmers. When debris and dirt fall into the pool because of any reason, it can get broken down to the point where it isn’t visible to the naked eye and is perceived as a cloudy layer. 

Most organic impurities like dirt, leaves, and clay actually react with chlorine. This increases the combined chlorine levels, reducing free chlorine, which can further heighten the pool cloudiness risk.

How to fix this:

The solution to making a dirty pool clear is to get rid of the dirt. This means getting serious about filtration, using a pool vacuum if you have to, and then adding pool chemicals. Above all, you need to maintain healthy chlorine levels and a decent pH balance.

How Do I Clear Cloudy Pool Water?

Now that you know the different possible causes of cloudy pool water let’s look at a cohesive solution. You probably don’t want to try all the fixes for each possible cause. This section aggregates the solutions into a single pool-clarifying strategy. If you follow the steps covered below, you will have a clear pool in less than 48 hours.

Clean Your Pool With a Brush and Skimmer

The lowest-effort way to get started is to get rid of the dirt that is easy enough to get rid of. This can be done with a brush or a skimmer. Remember, anything that’s visible can get broken down until it becomes a cloud of particles. And you don’t want that.

Use a Pool Vacuum To Clean the Stubborn Deposits

Some dirt and debris on the pool walls can get chipped and dispersed into the water, making it cloudier with each circulation. It is better to get rid of it all together using a pool vacuum.

Balance Your Pool Water PH and Pool Chemicals

While foreign impurities need to be removed by cleaning, the chloramine buildup and calcium hardness need to be managed with appropriate pool chemical balance. For that, you need to test and add pool chemicals.

Check the Pool Filter and Speed Up Circulation

In case your pool filter needs backwashing or replacement, this is the stage to do it. If it is not clogged, then you can speed up circulation to improve water clarity. The sooner solid particles are removed from the pool water, the quicker your pool becomes crystal clear.

Shock Your Pool

If bacteria and other microbes are responsible for cloudiness, shocking your pool will help. If they’re not, shocking your pool won’t hurt. That’s why it is a good step to include in your pool clarifying process.

Add Pool Clarifier

Adding pool clarifier is the final step you should take when getting rid of cloudy water. People mistakenly assume that it should be the first solution because it supposedly requires the least effort. 

In reality, using a pool clarifier as a crutch can be expensive because you end up using it over and over without addressing the underlying cause. Only after you’ve fixed every possible issue by following the steps above should you use pool clarifier.

Is It OK To Swim in a Cloudy Pool?

It is not always OK to swim in a cloudy pool because the cloudiness indicates the presence of impurities or the lack of chemical balance, both of which can lead to medical problems among swimmers. Poor filtration can cause cloudiness, so you shouldn’t consider unclear water safe for swimming.

Final Thoughts

Your pool water is cloudy because your pool is full of particles that are less invisible than water. This is a very broad cause that encompasses pH imbalance, improper filtration, and a host of other causes. But generally, if you clean your pool, balance its chemicals, and add a pool clarifier, you should be able to get rid of the cloudiness.

Jed Arnold

Jed spent every year from the ages of 15 - 22 as a Lifeguard (Red Cross) and ages of 17 - 22 as a Certified Pool Operator (CPO). Between working for over a dozen facilities and owning a pool, he carries over a decade of pool experience.

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